Bis-(beta-amino acrylyl thiocarboxylate)of cyclic hydrocarbon alcohols

ABSTRACT

BIS-(B-AMINOACRYLYL) COMPOUNDS ARE PREPARED IN A PROCESS COMPRISING FIRST REACTING A CYCLIC HYDROCARBON WITH A CYANOACETYLATING AGENT TO FORM AN INTERMEDIATE, AND THEN REACTING THE INTERMEDIATE WITH AN ALCOHOL AND A HYDROGEN HALIDE FOLLOWED BY THE ADITION OF SODIUM BICARBONATE. THE COMPOUNDS ARE PARTICULARLY USEFUL AS HEAT STABILIZERS FOR CHLORINE-CONTAINING POLYMERS, EXPECIALLY POLYVINYL CHLORIDE.

United States Patent 3,810,930 BIS-(BETA-AMINO ACRYLYL THIOCARBOXYL-ATE) 0F CYCLIC HYDROCARBON ALCOHOLS Richard G. Parker, Brecksville,Ohio, assignor to The B. F. Goodrich Company, New York, N.Y. No Drawing.Original application Oct. 29, 1971, Ser. No. 193,998. Divided and thisapplication May 7, 1973, Ser.

Int. Cl. C07c 153/07 US. Cl. 260-455 R 3 Claims ABSTRACT OF THEDISCLOSURE Bis-(fi-arninoacrylyl) compounds are prepared in a processcomprising first reacting a cyclic hydrocarbon with a cyanoacetylatingagent to form an intermediate, and then reacting the intermediate withan alcohol and a hydrogen halide followed by the addition of sodiumbicarbonate. The compounds are particularly useful as heat stabilizersfor chlorine-containing polymers, especially polyvinyl chloride.

This is a division of application Ser. No. 193,998, filed Oct. 29, 1971.

BACKGROUND OF THE INVENTION Chlorine-containing polymers form a verylarge segment of the class of packaging materials. Their utility issomewhat limited, however, by their relatively low heat stability. Thisinstability evidences itself by darkening of the polymer and theemission of hydrogen chloride upon heat aging. Many different types ofcompounds have been employed to improve the heat stability ofchlorine-containing polymers, especially polyvinyl chloride. Thesestabilizers are divided into two general classes of compounds, metallicand non-metallic. The metallic types, especially the organo-metalliccompounds, have received much attention because they are quiteefficient. However, these stabilizers are highly restricted in thepackaging area due to limits on the types and amounts of metals that canbe present. Non-metallic stabilizers are used in these cases, but alwaysat a large loss in stabilizer efficiency.

SUMMARY OF THE INVENTION A novel class of non-metallic stabilizers hasbeen discovered that provides improved heat stability forchlofine-containing polymers. The compounds are bis(fi aminoacrylyl)derivatives of cyclic hydrocarbons.

DETAILED DESCRIPTION The bis(/3aminoacrylyl) compounds are of theformula H N R 0 an aryl group containing 6 to 18 carbon atoms; R is -H,CH or C H and A has the formula wherein R A is a cyclic hydrocarbonselected from benzene and naphthalene and alkyl derivatives thereof, ora cycloalkyl containing 5 to 8 carbon atoms in the ring and alkylderivatives thereof, and n=0 to 6.

Examples of such compounds are 1,4-bis-(fl-rnethoXy-B-aminoacrylyloxy)benzene; a,a'-biS([1-ethoxy-B-aminoacrylyloxy-1,4-dimethy1- benzene;

Patented May 14, 1974 Preferred are those compounds wherein Y is O or S;R is an alkyl group containing 1 to 18 carbon atoms; R is H; and where Ahas n==0 or 1 and R is a benzene or a cyclohexane radical. Examples ofsuch compounds are oz,oc'-bi$- (fi-ethoxy-p-aminoacrylyloxy)-1,4-dimethylbenzene;

a, x.'-bis- (,B-ethoxy-fl-aminoacrylylthio)-1,4-dimethylbenzene;

a,a'-bis (B-ethoxy-fi-aminoacrylyloxy)-1,4-dicyclohexane;

a-,u' -blS- B-octadecylthiofi-aminoacrylyloxy) 1,4-

dimethylbenzene;

and the like. More preferred are those compounds where R is a benzeneradical. Excellent results were obtained using a, m'-blS-,B-ethoxy-B-aminoacrylyloxy l ,4-dimethylbenzene anda,ab1s-(fi-ethoxy-B-aminoacrylylthio)-1,4-dimethylbenzene.

The bis(fi-aminoacrylyl) cyclic compounds are prepared m a three-stepprocess. In the first step, a dicompound of the formula wherein R and nare defined as above and Y is selected from the group consisting of DH,-SH, Cl, and --NH is reacted with a cyanoacetylating agent to make abis(cyanoaceto) intermediate.

Examples of the dicompounds are 1,4dihydroxy benzene;

1,4-di- (ot-hydroxymethyl benzene; 1,4-di- ('y-hydroxypropyl) benzene;1,4-di- (a-hydroxymethyl) cycloh exane; 1,4-di(mercapto benzene;

1,4-di- (a-mecaptomethyl) benzene; 1,4-di (fl-mercaptoethyl cyclohexane;1,4-diwchloromethyl benzene; 1,4-difi-chlorobutyl) benzene; 1,4-di-(amino benzene;

1,4-diot-aminomethyl benzene; 2,7-di- (hydroxy naphthalene;

and the like.

The cyanoacetylating agents have the formula wherein R is defined aboveand B is selected from the group of OH, Cl, Br, -OM where M is amonovalent or divalent metal such as Na, K, Ag, Pb, and the like, --ORwhere R is an alkyl group containing 1 to 8 carbon atoms, and

-O=l;HNR"3 salts wherein R is H or an alkyl group containing 1 to 8carbon atoms.

Examples of such compounds are cyanoacetic acid; ethyl cyanoacetate;butyl cyanoacetate; cyanoacetyl chloride; cyanoacetyl bromide; the Naand Ag salt of cyanoacetic acid; the triethylamine salt of cyanoaceticacid; and the like. Preferred are the compounds wherein B is OH, OCH OCH Cl, and O- HNR Examples of such are cyanoacetic acid, cyanoacetylchloride, methyl cyanoacetate, ethyl cyanoacetate, the triethyl ammoniumsalt of cyanoacetic acid, and the like.

The cyanoacetylating agent is reacted with the dicompound using abouttwo moles of cyanoacetylating agent for one mole of the dicompound,although an excess of the agent can be used. The reaction can beperformed without a solvent but preferably a solvent is used. Typicalsolvents are alkanes such as hexane and heptane, aromatics such asbenzene andtoluene, and dimethylformamide, dimethylsulfoxide, andethylenedichloride.

The reaction is preferably conducted in the presence of a catalyst. Thecatalyst is used in amounts from about 0.0001 mole to about 0.01 molefor acids, and about 0.1 mole to about 2 moles for bases. A dihydroxydicompound of the above formula readily reacts with a cyanoacid orcyanoacetate in the presence of an acid catalyst. The acid can be amineral acid such as hydrochloric acid or sulfuric acid, or an organicacid such as p-toluene sulfonic acid. A dimercapto dicompound reactswith a cyanoacetyl chloride or bromide in the presence of a base such asa tertiary amine. Typical amines are trimethylamine, triethylamine,N,N-dimethylaminline, and the like. The reaction between a dichloridedicompound and a cyanoacetic acid/amine salt requires no catalysts to beadded.

The temperature of reaction is from about 50 C. to about 150 C. Aconvenient manner in which to conduct the reaction is to run it at thereflux temperature of the solvent. In this manner, by-products such aswater can be removed from the system. Reaction times range from about 8to about 24 hours. Yields of the intermediate product are about 50%based on the amount of the dicompound used. The intermediate can beisolated by heating under reduced pressure to remove the solvent.

The intermediate product of step one is a bis(cyanoaceto) cycliccompound. This is reacted in step two with an alcohol or thioalcohol anda hydrogen halide.

The alcohol or thioalcohol is of the formula RXH wherein X is O or -S,and R is an alkyl group containing 1 to 24 carbon atoms or an aryl groupcontaining 6 to 18 carbon atoms. Examples of such-compounds aremethanol, ethanol, propanol, isopropanol, tertiary butanol, hexanol,n-octanol, n-decanol, n-octadecanol, and the like; phenol, benzylalcohol, 4-ethyl phenol, 4-tert-butyl phenol, l-hydroxypropyl benzene,and the like; ethyl mercaptan, t-butyl mercaptan, octyl mercaptan,dodecyl mercaptan, octadecyl mercaptan, and the like; mercapto benzene,benzyl mercaptan, 4-methyl benzyl mercaptan, and the like.

Preferred are those alcohols wherein R is an alkyl group containing 1 to18 carbon atoms. Examples of such are methanol, ethanol, butanol,octanol, decanol, dodecyl alcohol, octadecanol, octyl mercaptan, decylmercaptan, tetradecyl mercaptan, octadecyl mercaptan, and the like.

The alcohol, or thialcohol is used in amounts from about two moles toabout three moles per mole of the intermediate compound, but a largerexcess of alcohol can be used.

The hydrogen halide is anhydrous hydrogen chloride gas, hydrogen bromidegas, or hydrogen iodide gas. Preferred is anhydrous hydrogen bromide orhydrogen chloride gas. The amount of hydrogen halide used is from abouttwo moles to about three moles per mole of intermediate, but a largerexcess can be used. The reaction is preferably conducted in a solventfor the intermediate. Such solvents are the same as used in step one ofthe reaction, being hexane, benzene, and ethylene-dichloride, and thelike.

The temperature of the step two reaction is from about 10 C. to about 30C. Reaction times are from about 6 hours to about 10 hours. Yields areabout 90% based on the amount of intermediate used. The step two productis an alcohol or thioalcohol hydrogen halide salt complex of thecyanoaceto group on the intermediate.

The step two product can be isolated by cooling down and filtering thereaction mixture. The material can then be washed with colddichloroethane to purify it.

In step three, the salt complex of step two is added to a mixture ofsodium bicarbonate in water and dichloroethane. The reaction neutralizesthe salt complex. The resulting grouping is aB-alcohol-B-aminoethylidene group. The compound is dissolved in thedichloroethane phase which is extracted and heated under reducedpressure to isolate it. The compound can be purified by dissolving it inhot benzene and then adding hexane to the solution to precipitate itout. The step three reaction takes about one hour. Yield of thisreaction is about based on the step two salt complex.

The bis(B-arninoacrylyl) compounds have particular utility asstabilizers for chlorine-containing polymers, especially polyvinylchloride.

The compounds can be admixed with the polymers on two-roll mills,internal mixers such as banburys and extruders, and the like. The mixingis conducted in these cases at the melt conditions of the polymer. Apreferred method is to dissolve the stabilizer in a solvent, add this toa slurry of the polymer, and evaporate off the solvent(s).

The bis(fi-aminoacrylyl) compounds are used in amounts from about 0.1 toabout 5 parts by Weight based upon 100 parts by weight of the polymer,and more preferably from about 0.3 to about 3 parts by weight. They canbe readily used with other known stabilizers such as the organotinstabilizers, certain metals salts, fatty acid metal salts, ureaderivatives, phenolic antioxidants, polyhydric alcohols, andthiodialkionic esters.

Examples of chlorine-containing polymers which can be effectivelystabilized by the compounds of this invention are polyvinyl chloride,polyvinylidene chloride, chlorinated polyethylene, and polymerscontaining units of chlorinated monomers such as vinyl chloride,vinylidene chloride, and the like.

The following examples serve to more fully illustrate the invention.

- EXAMPLE I Para xylylene bis(cyanoacetate), an intermediate product ofstep one, was prepared using the following recipe:

p-Xylene-ot,ot'-diol, mole 0.5 Cyanoacetic acid, mole 1.0 Concentratedsulfuric acid, mole 1 0.0001 Dry benzene, milliliters 500 Mo1es ofH2804, sulfuric acid being 96% by weight in water.

The ingredients were charged into a reactor vessel equipped with anagitator, condenser with a trap, and thermometer. The reaction wasconducted under a dry nitrogen gas sweep.

Ingredients were heated to the reflux temperature of the solvent,benzene, about 80 C. In this manner, water produced from theacid/alcohol esterification was removed from the system. The time ofreaction was set as the time required to trap of the theoretical amountof water. The reaction solution was then cooled to room temperature andthe benzene evaporated olf under reduced pressure. The solids weredissolved in a 9/1 ethanol/benzene solution. Charcoal was added and thesolution filtered hot (=60 C.) through Celite. After cooling thefiltered solution to about 0 C., the compound crystallized andprecipitated. The mix was then filtered, the crystals collected andwashed with cold ethanol, and dried under reduced pressure. 68 grams ofsolid were collected, reflecting a yield of 50% based on the amount ofdiol charged. The crystals had a melting point of 85 C.- 86 C., andtheir infra-red (IR) and nuclear magnetic resonance (NMR) spectra wereconsistent with the desired structure.

The reaction was repeated using p-toluene sulfonic acid as the acidcatalyst with similar results.

EXAMPLE II Para-xylylene-bis-(cyanoacetate) was also prepared usingcyanoacetyl chloride in place of cyanoacetic acid as thecyanoacetylating agent. The recipe used was:

p-Xylene-a,e-diol, mole 0.5 Cyanoacetyl chloride, mole 1.0N,N-dimethylaniline, mole 1.0 1,2-dichloroethane, milliliters 500 Thediol, the amine, and the solvent were added to the reactor vessel andthe cyanoacetyl chloride added dropwise to the solution at roomtemperature. The solution was then heated to reflux (about 84 C.) for 90minutes. The solution was cooled, diluted with 200 milliliters of water,and filtered. The filtered liquor separated into two phases. The bottomlayer, the dichloroethane layer, was separated and evaporated to isolatethe solids. These solids are treated as in Example I to recover andpurify the intermediate product. The yield obtained was about 50%.

The reaction was repeated using p-xylene-a,a'-dithiol in place of thediol with similar results. The intermediate product was thenp-xylylene-bis-(cyanothioacetate).

EXAMPLE III A third method of preparing p-xylylene-bis-(cyanoacetate)comprised using p-xylene-a,a'-dichloride in place of the diol. Therecipe was:

p-Xylene-u,u'-dichloride, mole 0.1 Cyanoacetic acid, mole 0.2Triethylamine, mole 0.22 1,2-dichloroethane, milliliters 150 Thecyanoacetic acid, amine, and 100 milliliters of solvent were charged tothe reactor vessel. This resulted in the formation of an acid/amine saltof the cyanoacetylating agent. The dichloride was dissolved in 50milliliters of solvent and added to the reactor vessel solution. Thesolution was heated to reflux, about 84 C., for 24 hours. The solutionwas filtered to remove triethylene hydrochloride and the liquor treatedas in Example I to recover and purify the product. Yield was 44%.

EXAMPLE IV In step two of the process, ned-bis-(B-ethoxy-p-aminoacrylyloxy)-l,4-dimethylbenzene was preparedfrom the cyanoacetate intermediates prepared in the above examples.0.075 mole of p-xylylene-bis(cyanoacetate), 0.165 mole of dry ethanol,and 250 milliliters of dry 1,2- dichloroethane were added to a reactorvessel. The solution was cooled to 0 C., 0.165 mole of anhydroushydrogen bromide gas was added, and the vessel sealed. The temperaturewas held at 0-5 C. for 6 hours. The vessel was opened, and the solutionfiltered to remove the alcohol/hydrogen halide salt of the intermediate.This was Washed with cold dichloroethane and dried under reducedpressure. The salt yield was 95% (37 grams) based on the step oneintermediate. In step three, a mixture of 0.9 mole of sodiumbicarbonate, NaHCO was prepared using 400 milliliters of water and 300milliliters of dichloroethane. The intermediate salt of step two wasslowly added to this mixture while keeping the temperature at 0 C.-5 C.After addition, the mixture was stirred for 30 minutes and then allowedto separate. The dichloroethane was separated and dried to isolate thefinal product. The amount recovered was 21 grams, reflecting a yield 78%based on the step two sale complex. The product was purified bydissolving it in hot benzene and then precipitating it out by addinghexane to the solution.

Using the procedures as given in Examples I to IV, the followingcompounds were prepared:

a, nU-bis- (B-ethoxy-fl-aminoacrylyloxy) -1,4-dimethyl benzene;

oz, a'blS- (18-ethoxy-B-aminoacrylylthio)- 1,4-dimethylbenzene;

a al-bis-(p-benzyloxy-B-aminoacrylyloxy)-1,4-dimethylbenzene;

a,a-bis- (,B-octadecylthio-fl-aminoacrylyloxy) -1,4-

dimethylbenzene;

od-bis-(B-ethoxy-fi-aminoacrylylamino)-1,4-dimethylbenzene;

u i-bis-(p-ethoxy-aaminoacrylyloxy)-1,4-dimethylcyclohexane.

EXAMPLE V Three of the his (p-aminoacrylyl) compounds were evaluated asstabilizers for a poly-vinyl chloride (PVC) resin. Testing consisted ofheat aging the samples at 180 C. and observing the onset of rapidhydrogen chloride (HCl) evolution.

The samples were prepared by dissolving the stabilizer in a solvent suchas benzene, making a slurry of polyvinyl chloride (PVC) powder in asolvent (benzene), mixing the two and evaporating ofi the solvent underreduced pressure until a free-flowing powder is obtained. milligrams ofthe treated PVC powder is weighed into a sample dish and placed into aheated glass tube. A pre-heated carrier gas is let in at the bottom ofthe tube and it flows around the sample dish, sweeping: any volatileswith it. The carrier gas is funneled into and bubbled through neutralwater in a conductivity cell. The ion change due to the HCl carried bythe gas into the water is measured and recorded. Although this methodcan allow for direct calculation of the HCl amount emitted by the PVC,the test is usually used in a relative manner. Thi means that the actualHCl emission is not measured but the rate of emission is observed andcompared to a non-stabilized PVC. The HCl emission in a stabilized PVCfollows a pattern in which there is an induction period followed by arapid, continual HCl emission. A plot of ion concentration (HClemission) versus time will show an almost horizontal induction periodfollowed by a rapid, almost vertical emission period. The point ofintersection of a line drawn to the slope to each of these periods istaken as the point of failure of the stabilizer. At times there is asmall change in slope of the ion concentration curve between theinduction period and the rapid emission period. This is considered partof the induction period as the HCl emission is still being eifectivelyinhibited.

Included in the test was an unsta'bilized PVC sample as a control and asample of PVC containing a bis(aminocrotonate) as described within US.Pat. 3,518,224. The stabilizers were used at 2.0 parts by weight.Results are listed in the following table.

The stabilizers were also evaluated in a heat aging test wherein time todiscoloration of PVC was the measure of their efficiency. Thestabilizers were added to the PVC by dissolving it in benzene, addingthe solution to a PVC slurry in benzene, and evaporating off thesolvent. The PVC was then milled on a two-roll mill, sheeted off atabout a 50 mil thickness, and cut into samples. The stabilizers wereused at the level of 2.0 parts by weight per hundred parts of PVC. Thesamples were placed in a static air oven at 180 C. and checked everyminutes for color development. The time to reach a black color wasmeasured. Results are in the following table.

Time to black color Stabilizer:

(min.) None A 70 wherein X is selected from the group of -O-- and S--; Yis S; R is selected from the group consisting of an alkyl radicalcontaining 1 to 24 carbon atoms and an aryl radical containing 6 to 18carbon atoms; R is H, CH 0r --C H and A has the formula wherein R is acyclic hydrocarbon radical selected from the group consisting ofbenzene, naphthalene and cycloalkanes of from 5 to 8 carbon atoms, andn=0 to 6.

2. A compound of claim 1 wherein Y is S; R is an alkyl group containing1 to 18 carbon atoms; R is -H; and R is selected from the groupconsisting of benzene, cyclohexane, and alkyl derivatives thereof, andn=0 to 1.

3. A compound of claim 2 of the formula No references cited.

LEWIS GOTTS, Primary Examiner D. R. PHILLIPS, Assistant Examiner U.S.Cl. X.R.

260-570 K, 570 TP, 485 R, 583 P, 563 R, 45.85, 45.75, 45.9 R

